I recently picked up a Durst L900 with a CLS450 color head, an EST 450 transformer and a CNA 450 analyser. After about 4 days the EST 450 made a clunk noise and stopped working. I am not at all electrically minded so would appreciate any help or advice. What trade would I take it to for possible repair? Some photos of the unit with the cover off (https://goo.gl/photos/tS46bVqcMKk8q6Cu9). Is it interchangeable with a TRA 450? Are they similar circuitry? A friends father said that if I have a schematic for the EST 450 he will have a look at fixing it. I have been able to find a schematic for the TRA 450 but not the EST 450. Is there a reliable (non Durst) alternative to the EST 450?